Add invitations to calendar automatically.

Up until a few days ago, I only had to hover over a proposed/confirmed date/invitation in Mac Mail to add this date to my Mac Calendar. And once it was added to the calendar, you could find the original email via the calendar date. What happened to this feature? I can't find it anymore in either mail preferences nor calendar preferences.

I used it multiple times a day and it's just not the same enter the date manually in my Calendar. Has the location of the setting been changed?